peter Posted November 13, 2012 Report Posted November 13, 2012 Sadly, the Kevlar O2 tank in our 231 has reached its 15 year life limit and needs to be replaced. Can anyone offer any suggestions and/or recommendations on the best place to buy a replacement tank? We've also been toying with the idea of downsizing to a smaller 77cf 3HT steel tank since we never seem to come close to using all the O2 in the bigger tank (thank you Oxymizer!) and the weight of the smaller steel tank is about the same as the larger tank we have now. Thoughts and input on this idea are welcome, as well as any Pireps on the real-world usefulness of the 77cf tank. Many thanks in advance, Peter 82 M20k 231
231Pilot Posted November 13, 2012 Report Posted November 13, 2012 Mountain High Oxygen sells direct (http://www.mhoxygen.com/). Aerox sells through Aircraft Spruce. Both are good options. Got this info from Vince on MAPA List. I am replacing mine too.
AndyFromCB Posted November 13, 2012 Report Posted November 13, 2012 http://www.hrd-aerosystems.com/ has PMA kevlar tanks, all tanks are made by the same company anyway, but HRD has a PMA tank for Scott/Zodiak with same part number.
Cabanaboy Posted November 13, 2012 Report Posted November 13, 2012 Precise Oxygen Equipment http://preciseflight...neral-aviation/
N201MKTurbo Posted November 15, 2012 Report Posted November 15, 2012 I have a 115 cu ft steel tank that has some life left. Let me know if you are interested and I will run out to the hanger and get the numbers off of it.
peter Posted November 15, 2012 Author Report Posted November 15, 2012 @N201MKTurbo Thanks, but no - the weight delta between composite and steel is a non-starter for us. I appreciate the offer all the same. Peter
DonMuncy Posted November 15, 2012 Report Posted November 15, 2012 Peter, Not to question your decision. How many pounds difference is there between the two.
DonMuncy Posted November 15, 2012 Report Posted November 15, 2012 Wow, I had no idea. I would not have thought my steel tank would have weighted much over 16 lbs. Either my ability to guess weight is pretty far off, or those Kevlar tanks are really light (or both).
peter Posted November 15, 2012 Author Report Posted November 15, 2012 I found tank weights here: http://www.airportshop.com/aviation_oxygen/cylinder_specs.pdf A fully charged 115cf composite tank is 28lbs. Steel is 44lbs. The fully charged 77cf steel tank is 29lbs, or roughly the same as the bigger Kevlar tank.
FBCK Posted November 16, 2012 Report Posted November 16, 2012 Peter I replaced my 77 cb/ft 3HT thin walled tank this year with the same and had the regulator rebuilt at the same time. The tank was $1300 and was purchased from the below link (good people) and had the regular done here in Canada ($700). I seem like my tank is large enough, went for 4 hours at 15000 feet with two of use and used 18% of the supply. http://www.airportshop.com/aviation_oxygen/cylinders.html
SkyBound Posted January 20, 2013 Report Posted January 20, 2013 I have recently acquired an M20K with a 77 CF 3HT steel cylinder in the baggage compartment (see attached photo). The cylinder is at the end of its 25 year life and needs to be replaced. My option is to replace it with the same steel cylinder - $1,300 or a composite cylinder for $1,700 plus cost of labor for minor modifications. I would only gain 10 lbs with the composite cylinder and am currently leaning to just staying with the steel as I don't see the value in additional cost just to gain 10 lbs. What advice does the group have for me on this decision? I have also seen the option of having the cylinder installed in the tail cone in other airplanes however my mechanic is saying that to get approval for that in my airplane would be very costly. Any suggestions here? Thanks in advance! --Alex
DonMuncy Posted January 20, 2013 Report Posted January 20, 2013 What year is your K. Mine is an 82 model and has the steel tank in the tailcone. I don't claim to be an expert, but it would seem that if it is legal in my plane, it should be in yours. Have you looked at your logs to see if someone moved the tank into the baggage compartment. Maybe someone more knowledgeable will chime in with better info. 1
RJBrown Posted January 20, 2013 Report Posted January 20, 2013 I would suspect that Skybound's K is a 79. 80 and newer had oxygen as standard equiptment. Any oxygen in 1979 planes was added later. You would have to find out what is installed. This instal is obviously not a retrofit with later parts. A retrofit with later parts may only need a sign off and not an STC or single approval. More weight further back may allow less weight in the tail. Most Ks have bob weights in the tail to help with balance. 1
SkyBound Posted January 20, 2013 Report Posted January 20, 2013 Don and RJ, Thank you for your responses. My K is a 79 and the Oxygen was added in 1985. How do you suggest I proceed to confirm that I can use later parts to move the tank into the tailcone? If I find out that I am able to move the tank into the tailcone, do you suggest I go with the composite? On the contrary, if I just replace the tank and keep the set-up in the baggage compartment would you recommend steel or composite? Thank you again. --Alex
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